At the time of treating coronary arterial stenosis, a minimally invasive treatment using a catheter has been used. Performing this surgical operation involves injecting a radiopaque material for the purpose of checking the position of the catheter and/or the state of the stenosed part. In addition, flushing with physiological saline is performed for securing the contrast of an image as required. Furthermore, a pressure monitor for measuring (detecting) the arterial pressure and displaying the arterial pressure is always connected to this circuit, so as to check the arterial pressure, and the pressure monitor is disconnected at the time of injecting the radiopaque material or physiological saline.
To carry out these operations, the flow channel in the circuit has to be changed over. As a way of changing over the flow channel, conventionally, a three-in-series type three-way cock has been used.
In the case of the three-in-series type three-way cock, however, there are three cocks and the three cocks have to be operated, so that the operations are intricate and it is impossible to achieve speedy changeover of the flow channel.
A device described in Japanese Patent Laid-open No. Hei 9-108360 describes an arrangement for simplifying these operations, but the device has a problem that only changeover between a radiopaque material route (flow channel) and a pressure monitor route can be performed, and it is impossible to make a changeover to a physiological saline route. Besides, an addition of a physiological saline route is difficult to realize, since such an addition complicates the mechanism.